Rotary switch with shock absorbing drive



,1957 w. LoHs 2,808,460

ROTARY SWITCH mm snocx ABSORBING DRIVE Filed Nov. 15, .1952 s sheets-sheet 1 Inventor:

Oct. 1, 1957 w. LOHS 2,808,460

ROTARY SWITCH WITH SHOCK ABSORBING DRIVE Filed Nov. 13, 1952 3 Sheets-Sheet 2 W' -j0s.

Oct. 1, 1957 Filed Nov. 13; 1952 w. LOHS 2,808,460 ROTARY swrrcn wrm snack assomams DRIVE.

3 Sheets-Sheet Q 'ment by the stop pawl.

2,808,460 Fatented Oct. 1, 1957 ROTARY SWITCH WITH SHOCK ABSORBING DRIVE Willy Loh's, Munich, Germany, assignor to Siemens &

Halske, Aktiengesellschaft, Munich, poration of Germany Application November 13, 1952, Serial No. 320,198 Claims priority, application Germany November 20, 1951 29 Claims. (Cl. 179-2751) This invention is concerned with a rotary switch for signalling systems, especially for automatic telephone systems, comprising a gear drive and a stepping motor therefor.

It is known to control the motor of such a switch by creating magnetic fields so that its wipers are stopped after being set in engagement with desired bank contacts. The time required from the moment when the wipers reach the desired bank contacts until the switch is stopped introduces certain limitations so far as the stepping speed is concerned. A satisfactory engagement of the wipers with the bank contacts is obtained only by keeping close manufacturing tolerances for the parts of the drive mechanism, because such engagement depends on a certain angular position of the motor armature.

The object of the present invention is to obtain a satis- I factory stopping of the rotary switch with gear drive which is independent of the stepping motor. This object is realized by stopping the switch with the wipers in engagement with the desired bank contacts by means of a pawl coacting with a locking or stopping wheel and by absorbing inertia forces, which are thereafter still opera tive, by means of a spring-controlled coupling which is inserted in the gear drive of the switch. Close manufacturing tolerances for the parts of the drive mechanism are thereby eliminated. Relative narrow bank contacts may be used and the spacing between individual bank contact may be made rather small, even at great stepping speed of the switch, thus making it possible to produce switches of relatively small size.

Damage to the gears of the drive by the instantaneous stopping is prevented by the spring coupling, and the brake path in such coupling may be utilized for pressing into engagement with the bank contacts the wipers which are rotated out of engagement therewith.

Examples of the invention are shown in the accompanying drawings, in which Fig. 1 shows a switch comprising a locking or stopping pawl for engagement with the drive wheel of the switch shaft and a spring coupling carried by a gear set disposed between the drive pinion of the motor and the drive wheel;

Figs. 2 and 3 illustrate a switch comprising a switch shaft and having a special stopping wheel for engage- The spring coupling is positioned between the drive wheel and the stopping wheel, both of which are carried by the switch shaft; and

Fig. 4 shows a switch having two stop or locking pawls, one for coaction with a special stop wheel and one for coaction with the drive wheel of the switch shaft, the spring coupling being again disposed between the drive wheel and the stop wheel, both of which are arranged on the switch shaft.

The switch shown in Fig. 1 is driven by a pinion 1 which is disposed, for example, on the drive shaft of a drive or stepping motor. The rotary motion of the pinion is transmitted to an intermediate gear comprising the gear wheels 2 and 3. The gear wheel 2 is rotatably on the shaft 4 and gear wheel 3 is fixedly secured thereto. Between the gear wheels 2 and 3 is disposed a spring coupling comprising a follower pin 5 carried by the gear wheel 2. The shaft 4 is provided with a follower 6. The spiral spring 9 is journalled on the shaft 4 and its legs 7 and 8 lie against the follower pins 5 and 6.

The rotary motion of the gear wheel 3 is transmitted to the drive gear wheel 10 carried by the shaft 11 of the switch. Numeral 12 indicates a test relay comprising an armature 13 having an angular extension end 14. The latter (14) is in interlock engagement with the nose 16 extending at an angle of about from the rotatably journalled armature 15 of the magnet 18, such armature forming a stop pawl or locking lever. The stop pawl or lever 15 has a stop tooth 17 of a shape conforming to the grooves between the teeth of the drive wheel 10. A spring 19 is provided for biasing the armature 15 (stop or locking lever) in the direction of the switch shaft.

The operation is as follows:

The magnet 18 is energized responsive to the seizure of the switch, attracting the lever 15 with its stop pawl 17, thus retracting the stop tooth 17 from the drive wheel 10. The angular extension 16 of the lever 15 slides along the end of the extension 14 of the armature 13 of the test relay 12, and as soon as the end of the extension 16 is aligned with the inner surface of the extension 14, the latter will move in back of 16, locking the lever 15 in attracted position. The released armature 13/14 of the test relay 12 thus holds the lever 15 in its actuated position. The magnet 18 thereafter deenergizes.

The motor of the switch is now actuated and the consequent rotary motion of the pinion 1 is transmitted to the drive gear wheel 1t? through the medium of the intermediate gears 2 and 3. The arrows indicate the direction of rotation of the various gear wheels. The test relay 12 is in known manner energized when the test wiper of the switch reaches the desired bank contact on which it should be stopped. The test relay, in energizing, has to furnish only the force required for moving the surface of the extension 14 relative to the narrow contacting edge of the extension 16 of the stop lever 15. The working stroke of the armature 13 is accordingly very short. The extension 16, and therewith the lever 15 and its pawl 17, is therefore released within the short energizing interval of the test relay 12, and the lever 15 is drawn in the direction of the shaft 11 by the force of the spring 19, caus ing the stop pawl or tooth 17 to fall with an impact into the space between two adjacent teeth of the drive wheel 19.

The force which has to be produced by the test relay 12 is very small. The masses which have to be moved by the test relay are likewise very small, and its energizing interval can therefore be extremely short. The time between the energization of the test relay 12 and the operative actuation of the stop lever 15 being correspondingly short, it follows that the switch can be rotated at higher switching speed and the wipers will be reliably stopped in engagement with the bank contacts determined by the testing operation of the test wiper.

The impact action of the pawl 17 of the lever 1.5 causes instantaneous stopping of the driven gear wheel 10 and therewith stopping of the rotation of the wiper carrier coacting therewith. In order to avoid as far as possible damage to the teeth of the drive gear wheel 11 there is provided the spring coupling 5-9 which is disposed between the gear wheels 2 and in The inertia forces of the wheels 2 and 1 and of the motor (not shown), which is stopped responsive to the testing operation of the switch, are absorbed by the spring coupling 5-9. The follower 5 acts in the direction indicated by the arrow upon the end of the spring leg 7 until the inertia forces are equalized or dissipated by the tension of the spring 9 when the rotating parts 1, 2 and also the motor come to a stop. The reactive force stored in the spring 9 then acts in opposite direction, and the gear wheel 2 and pinion 1, together with the coacting rotary parts of the motor, are forced by the follower pin 5 in a direction opposed to that indicated by the arrow, until the follower 5 lies against the leg 8 of the spring.

The rotary switch according to Figs. 2 and 3 has a stepping motor 21 carrying upon its shaft 122 a pinion 23 which is in engagement with a gear wheel 24 mounted on a shaft 25. The shaft 2 also carries a wheel 245 which is in engagement with a drive wheel 27 disposed upon the switch shaft 28 which also carries a stop wheel 29. The drive wheel 27 is provided with a follower pin 30 which projects through an opening 311 in the stop wheel 29 which carries a follower pin 32. The legs 32 of a spring 35 are in normal position of the shaft 5% in engagement with the follower pins 3d, 32. The drive Wheel 27 carries a switching pin 36 for controlling a wiper carrier 357 which is rotatable about a pivot 38 carried by the a stop wheel 29. Numeral 3% indicates a wiper.

The wiper carrier 37 also serves for controlling a set of contacts 4% disposed on the stop wheel 29 and is provided with a leaf spring 41, the free end of which coacts with a slip ring 42. The leaf spring 41 and the slip ring 42 serve for supplying current to the wiper 39. Numeral 43 indicates bank contacts.

The stop pawl or lever for the stop Wheel 29 is formed by a leaf spring 4-4- which is included in a pile of contact springs 45 and crimped at 46 to form a pawl for stop engagement with teeth of the stop wheel 29.

An insulating nipple 4-7 extending from the leaf spring 44 controls the contact springs The angularly bent free end of the spring 44 is in interlock engagement with the similarly bent end of the armature 48 of a test relay 49. A magnet 5% is provided with an armature Eli for restoring the stop pawl 46.

The operation of the arrangement, Figs. 2 and 3, is as follows:

The stepping motor 21, upon being switched in, rotates the pinion Z3, and the rotation of the latter is transmitted to the drive wheel 27 over the gear wheels 24 and 26. The direction of rotation is indicated by the arrows. The rotary motion also affects the stop wheel 2& by cooperation of the follower pins 30/32 with the legs 33/34 of the spring 35. The test relay 4-9 will energize in known manner when the test wiper (not shown) reaches the desired bank contact on which the switch wipers should stop. The armature as is attracted, releasing the end of the spring 44-, and the pawl 46 carried thereby snaps into the space between two adjacent teeth of the stop wheel 29. The contact springs 45 are coincidently actuated and open the associated circuit for the stepping motor 211..

The stop wheel 29 is suddenly arrested by the impact action of the pawl 4-6. The inertia forces of the drive comprising the motor, gear wheels 24/26 and the drive wheel 27 cause the drive wheel 27 to continue to rotate and to press the follower pin 30 against the leg 33 of the spring 35. The spring leg 3 is held in position by the follower pin 32, and the spring is thus tensioned, as indicated in Fig. 3, until the spring force and the rotary forces of the drive are completely equalized or dissipated. A detent or locking spring 52 must at this instant fall in .back of a tooth on a wheel 53 carried on the motor shaft 22. The drive is thus stopped or arrested in the position shown in Fig. 3. The drive wheel 27 has in this manner been angularly displaced relative to the stop wheel 29 by the angular amount of the displacement of the follower pins 30/32. The switch pin 36 on the drive wheel 27 rotates the wiper carrier 37 by the additional amount of angular rotation and presses the wiper 39 against the associated bank contact. The rotation of the wiper carrier 37 also presses the current supply spring all against the associated slip ring and actuates the set of contacts 4th.

The stroke of the armature 48 of the test relay 49 to release the stop spring is again very short, and the forces required for the operation of the test relay are accordingly relatively small. Extremely fast energization can therefore be provided for with smallest structure of the test relay. The switch can be operated at great speed and the stopping thereof at desired bank contacts is reliably secured.

The release of the switch is initiated by switching in the electromagnet Ell. The armature Sit rotates clockwise and presses upon the stop spring 4-4, thereby lifting the stopping pawl 46 from the teeth of the stop wheel 29. The test relay 49 releases upon release of the switch. The stop or locking spring 44 again interlocks the end ofthe armature 43 as shown. The magnet 5t} thereupon deenergizes.

After the stop pawl 46 is retracted from the stop wheel 29, the forces stored in the spring 35 and in the current supply spring 51 and contact springs 49 cause rotation of the stop wheel 29 in the direction of the arrow (Fig. 3) until the follower pin 32 is again in engagement with the spring leg 33. This rotation of the stop wheel 29 causes the wiper carrier 3'7 to rotate counterclockwise, due to the force exerted by the current supply spring 41 and the contact springs 4 thereby lifting the wiper 39 from the associated bank contact. The parts are then again in the position shown in Fig. 3. Depending upon the particular use of the switch, it may remain in this position until it is again taken into use. There is of course the possibility to start the stepping motor again so as to rotate the switch into a certain start position. The switch of Figs. 2 and 3 shows only one wiper which is pressed against the associated bank contacts by utilizing the inertia forces remaining after arresting its rotation. If there are several wipers they may be disposed one next to the other along the pivot pin The switch according to Fig. 4 is also operated by a stepping motor, of which only the armature 54 and the pinion 55 are shown. The pinion 55 meshes with the drive wheel 56 which is rotatably disposed on the switch shaft 57. Fixedly connected with the shaft 57 is a stop wheel The drive wheel 56 has a follower pin 59 which projects through the opening 60 in the stop wheel 58. The latter carries a follower pin 61 which may be riveted thereto. Alongside the follower pins SW61 are the legs 62/63 of a spring 64. The stop wheel 58 carries a pivot pin 66 for rotatably journalling a Wiper carrier 65. Numeral 67 indicates a switch wiper and 6:; bank contacts. The stop wheel 53 also carries a pin 69 for limiting the rotary motion of the wiper carrier 65. The follower pin 74) of the drive wheel 56 causes, responsive to rotation of the drive wheel, angular displacement of the wiper carrier under the action of a spring 71. Numeral 72 indicates the current supply spring which, in the actuated position of the wiper carrier 65, contacts a slip ring 73. The stop or locking pawl for the stop wheel 5% is indicated at 7 The pawl is released for stop engagement with the wheel 58 by the armature 75 of a test relay 76. The switch is also provided with a locking pawl 77 for engagement with teeth of the drive wheel 56. From the pawl 77 extends a locking spring 78 having an angularly formed end for engagement with a stop or locking tooth 79 which is suitably secured on or formed by a structural part of the switch. The lower end of the locking pawl 77 is pivotally mounted at 80 on a lever 81 which in turn is pivoted at 82. The free end of the lever 81 is normally held against a stop 83 by the action of a spring 34-. A spring 85 is provided between the lever forming the locking pawl 77 and the lever 81 which exerts, through the medium of the arm 89, an inward pressure on the lever forming the pawl 74. In the interlock position of the parts as shown in Fig. 4, such pressure acts against the angular end of the armature 75 of the test relay 76. The locking pawls 74 and 77 are controlled by the armature 86 of the magnet 87. A set of contact springs 88 is controlled by the free end of the lever 81.

The operation of the arrangement, Fig. 4, is as follows:

The armature 54 and the pinion 55 will rotate responsive to switching-in of the stepping motor. The pinion 55 rotates the drive wheel 56, and the rotation of the latter is transmitted to the stop or locking wheel 58 by cooperation of the follower pins with the legs of the spring 64. When a test wiper (not shown) of the switch reaches the bank contact on which it should stop, the test relay '76 will energize and actuate its armature 75 through a short stroke, to release the lever forming the pawl 74, and this pawl will fall between correspondingly positioned teeth of the stop wheel 58, thereby releasing the support for the arm or member 89 to cause the pawl 77 to move inwardly into stop engagement with two adjacent teeth of the drive wheel 56. The locking spring 78 engages the locking tooth 79 before the pawl 77 is in fully released position in the corresponding teeth of the wheel 56. Accordingly, the spring 78 is lifted from the pawl 77 when the latter is in fully released position.

The engagement of the pawl 74 with the stop wheel 58 causes the latter to stop. The continued rotation of the motor and the wheel depresses the pawl 77 downwardly, causing clockwise rotation of the lever 81 about the pivot 82 against the force of the spring 84. The angular end of the locking spring 78 slides during this phase of the operation along the tooth 79 until it falls into this locking tooth. The free end of the lever 81 has at that time actuated the set of contact springs 88 to interrupt the circuit of the stepping motor. The pawl 77 is moved further, against the pressure of the spring 84, by the inertia forces of the drive wheel 56 acting on it. After the rotary forces are dissipated, the spring 84 will assert itself and move the lever 81, and therewith the pawl 77, upwardly, until the end of the spring 78 engages the flank of the tooth 79.

The drive gear wheel 56 therefore is, after release of the pawl 74, rotated by an angular amount on. After the stop wheel 58 is arrested by the pawl 74, the additional rotation of the drive wheel 56 will press the follower pin- 59 against the spring leg 63, forcing this spring leg outwardly and thereby tensioning the spring 64. The follower pin '70 extending from the drive wheel 56 also partakes in its additional inertia motion and moves relative to the stop wheel 58. The pull of the spring 71 is now exerted on the wiper carrier 65 to rotate it about its pivot 66 until it lies against the stop pin 69. The wiper 67 is now pressed against the corresponding bank contact. The locking spring 78 falls at the same moment in back of the tooth 79, as already described. The further rotation of the drive wheel 56 occurring after the release of the locking spring 78 does not affect the operative position of the wiper carrier 65, but is merely effective to further tension the spring 64 by the motion of the follower pin 59, thus supporting the described brake action effected by the pawl 77 and the spring 84. Once the inertia forces are dissipated, the tension of the spring 64 will support the described operation of the drive wheel 56. The follower pin 78 will be angularly aligned with the stop pin 69 when the locking spring 78 reaches the flank of the tooth 79.

The switch is restored by the energization of control magnet 87 which attracts its armature 86, moving it in clockwise direction. The armature presses the stop spring forming the pawl 74 to the right until its free end snaps into interlock engagement with the angular end of the armature 75 of the test relay 76. The arm or member 89 is likewise affected to move to the right the spring carrying the pawl 77. The spring pawl 78 is disposed next to the locking tooth 79. The spring 84 rotates the lever $1 counterclockwise into engagement with the stop 83, thereby also restoring the pawl 77 to the position shown in Fig. 4 and also restoring the set of contacts 88.

When the pawl 74 leaves the teeth of the stop wheel 58,

the force of the spring 64 will be exerted to cause the spring leg 62 to-press against the follower pin 61, to rotate the stop wheel 58 clockwise until the two spring legs are positioned alongside the pins as shown in Fig. 4. The stop pin 69 moves with the clockwise motion of the stop wheel 58 away from the wiper carrier 65, and the follower pin 70, in cooperation with the spring 71, causes the wiper carrier 65 to rotate counterclockwise, thereby lifting the wiper 67 from the associated bank contact and the spring 72 from engagement with the slip ring 73. The magnet 87 is thereafter restored.

The switch may remain in the assumed position until it is again taken into use, or the stepping motor may be switched in again, to move it into a desired starting position.

Changes may be made within the scope and spirit of the appended claims which define what is believed new and desired to have protected by Letters Patent.

I claim:

1. For use in a telephone system, a rotary switch comprising a rotatable gear wheel carrying wiper means for selective engagement with associated bank contacts, motor means comprising a pinion for rotating intermediate drive gear means to impart rotation to said wiper-carrying gear wheel to rotate said wiper means relative to said bank contacts, a pawl for stopping rotation of said wipercarrying gear wheel when said wiper means reaches selected bank contacts, and a device for absorbing inertia forces stored during operative actuation of said switch in the masses of said motor means and in said wiper-carrying gear wheel and tending to continue operation thereof, said device comprising spring means for resiliently coupling said wiper-carrying gear wheel for rotation with said intermediate drive gear means.

2. The structure defined in claim 1, wherein said device comprises a spiral spring having two legs extending from its spiral, and follower means embraced by said legs in normal position of said motor means.

3. The structure defined in claim 2, comprising a pair of intermediate drive gear wheels, said coupling being disposed between said pinion and one of said drive gear Wheels.

4. The structure defined in claim 2, comprising a first intermediate gear wheel actuated by said pinion and a second intermediate gear wheel for driving said wipercarrying gear wheel, said first gear wheel being rotatably journalled on the shaft of said second gear wheel.

5. The structure defined in claim 4, comprising follower means extending from said first gear wheel and from said second gear wheel, respectively.

6. The structure defined in claim 2, comprising a shaft fixedly coupled to said intermediate drive gear means, said wiper-carrying gear wheel being rotatably journalled on said shaft, said spring-means being disposed between said Wiper-carrying gear wheel and said intermediate drive gear means.

7. The structure defined in claim 6, comprising a wiper carrier disposed rotatably by said wiper-carrying gear wheel, and a follower pin carried by said intermediate drive gear means.

8. The structure defined in claim 7, together with spring means which opposes the actuation of said wiper means.

9. The structure defined in claim 6, comprising a springbiased pawl for supporting the brake action of said device.

10. The structure defined in claim 1, together with means controlled by the actuation of said pawl for disconnecting said motor means, the inertia forces absorbed by said device being effective to store energy therein for cancelling the further inertia rotation of said motor means.

11. The structure defined in claim 10, together with locking means for controlling the rotation of said motor means due to said inertia forces.

12. The structure defined in claim 11, wherein said locking means comprises a stop wheel disposed upon the shaft of said wiper-carrying gear wheel, and a locking spring coacting' with said stop wheel.

13. The structure defined in claim 11, wherein said locking means comprises a stationary locking tooth, and a locking spring having a locking pawl coacting with said tooth.

14. The structure defined in claim 11, wherein said wiper means is rotated out of engagement with the bank contacts, and means controlled by the inertia forces which tend to continue rotation of said motor means for effecting engagement of said wiper means with the desire bank contacts.

15. The structure defined in claim 14, wherein said wiper means is rotatably journalled for rotation out of engagement with the bank contacts, and means controlled "by the inertia forces which tend to continue rotation of the motor means for moving said Wiper means.

16. The structure defined in claim 1, wherein said device comprises a spring-controlled pawl for engaging said wiper-carrying gear wheel in stop engagement therewith, inertia force exerted by said wiper-carrying gear wheel being effective to displace said pawl.

17. The structure defined in claim 16, comprising a lever arm, and spring means for said lever arm which opposes the motion of said pawl.

18. The structure defined in claim 17, comprising a locking spring cooperating with said pawl, a locking tooth for engagement with said locking spring, said locking spring engaging said locking tooth responsive to partial displacement of said pawl.

19. The structure defined in claim 18, wherein said inertia-controlled motion. of said motor means is can celled responsive to complete engagement of said pawl with said locking tooth. 20. The structure defined in claim 19, wherein said wiper means is pressed against the associated bank contacts coincident with the complete engagement of said locking tooth by said pawl.

21. The structure defined in claim 1, wherein said device comprising a pawl for engagement with said wipercarrying gear wheel, and a test relay which energizes when said wiper means reaches desired bank contacts for releasing said pawl to engage said wiper-carrying gear wheel.

22. The structure defined in claim 1, wherein said device comprises a pawl for engagement with said wipercarrying gear wheel, and a test relay which energizes when said wiper means reaches desired bank contacts for actuating its armature to release said pawl for engagement with said wiper-carrying gear wheel.

23. The structure defined in claim 1, wherein said device comprises a pawl for engagement with said wipercarrying gear wheel, and an electromagnet having an armature, said armature forming said pawl.

24. The structure defining in claim 1, wherein said device comprises a leaf spring forming a pawl for engagement with said wiper-carrying gear Wheel, and an electromagnet having an armature for controlling the op eration of said leaf spring.

25. An arrangement and cooperation of parts according to claim 1, wherein said device comprises a shaft carrying first intermediate drive gear means, and second intermediate drive gear means on said shaft for driving coaction with said pinion.

26. An arrangement and cooperation of parts according to claim 1, comprising a shaft carrying said intermediate drive gear means, said wiper-carrying gear wheel being rotatable on said shaft, a pawl for stopping coaction with said intermediate drive gear means, and a pawl for stopping coaction with said wiper-carrying gear wheel.

in rotary switching mechanism for use in an automatic telephone system having a rotatable shaft and toothed gear drive means for rotating it and a motor having a pinion for rotating said gear drive means and having a wiper carrier supporting wipers for engagement with desired contacts selected during rotation thereof responsive to rotation of said shaft, 2. device for arresting the rotation of said gear drive means and said wipers when said wipers reach desired bank contacts, said device comprisi g a toothed gear wheel included in said gear drive n. .s, an arm forming a stopping pawl, a member for interlocking with said arm to maintain said pawl in inoperative position during the rotation of said wipers, means responsive when said wipers reach said desired bank contacts for actuating said member to release said pawl for engagement with said toothed gear wheel to arrest rotation of said gear drive means so as to stop said wipers in alignment with the desired bank contacts, and springcontrolled means for absorbing inertia forces which tend 0 continue rotation of said gear drive means and said wipers.

28. The structure defined in claim 27, wherein said wipers are rotated by said gear drive means out of engagement with said bank contacts, and means acted upon by said inertia forces for moving said wipers into engagement with the selected bank contacts.

29. The structure defined in claim 27, wherein said device comprises a floating gear wheel included in said gear drive means, a follower carried by said floating gear wheel, a follower coacting with a driven gear wheel included in said gear drive means, and a spiral spring having two iegs extending normally in parallel for embracing said followers.

References Cited in the file of this patent UNITED STATES FATENT S 1,699,514 Aidendorff Ian. 22, 1929 2,146,228 Richter Feb. 7, 1939 2,687,790 Bruni Aug. 31, 1954 2,701,283 Broel Feb. 1, 1955 

